dm vdo indexer: Convert comma to semicolon

To ensure code clarity and prevent potential errors, it's advisable
to employ the ';' as a statement separator, except when ',' are
intentionally used for specific purposes.

Signed-off-by: Shen Lichuan <shenlichuan@vivo.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>